This web site was created for students at Austin Community
College who are enrolled in Biology 2304/2101 Human Anatomy. Lab
time is limited, and there is never enough time to become really
familiar with all of the histology slides. So to expand the available
options for reviewing histology, we have made images from the
slides used in the lab and placed them on this site along with
an explanation of how to identify them. Students who use this
site should, however, be aware that we have not been able to include
images of every specific slide for each tissue or organ. Using
this web site is not a replacement for quality lab time, where
students can benefit from the presence of a knowledgeable instructor.
what you see on these images compared to what you see on a microscope
hints on how to use this site
links to other explanatory pages at this site
links to related sites
slides - Most of the slides we used to make the images on this site came straight from the lab slide boxes, and are the same slides used by students in class. Most of these slides were made from tissue sections that are 8 to 10 micrometers thick. The microscope cannot focus on all of the cells at the same time, so the image you see in the microscope is partly obscured by tissue above or below it that is not in focus. Some images were made with a new set of thin section slides (1-2 micrometers thick). These slides produce a cleaner image because they allow us to focus on the entire depth of the tissue specimen at the same time.
abbreviations - Several abbreviations are used on this site. The most common types of abbreviations you will encounter on the site are either for describing the type of specimen preparation (for example, cross section = c.s.) or the general type of tissue (for example, connective tissue = c.t.). Here is a list of common abbreviations and what they stand for. You can refer back to this list while you are working on the other pages.
abbreviation term c.s. cross section (cut perpendicular to the axis, or across the structure) c.t. connective tissue e. epithelium l.s. longitudinal section (cut parallel to the axis, or along the structure) m. muscle n. nerve t.s. transverse section (cut perpendicular to the axis or across the structure) w.m. whole mount (the tissue was not cut before it was mounted on the slide) x.s. another abbreviation for cross section
magnification - On most tissues and organs we used the same three magnifications that students use in lab: 40X (scanning objective lens), 100X (low power objective lens) and 400X (high power objective lens). The "X" after the number means "times", so 100X means that the image you are looking at has been magnified 100 times. Each image is identified with the total magnifying power. For example, when you use the scanning objective lens (which magnifies an image by four times) you multiply its magnifying power (4X) by the magnifying power of the ocular lens (the one you look through has a magnifying power of ten times, or 10X) for a total magnification of 40X. Sometimes one or two levels of magnification were left out because they didn't provide any new information. The lowest magnification is always shown first, to simulate the way students should approach the slide in lab.
resolution - Some resolution was sacrificed to keep loading time to a minimum, so don't expect the images at this site to be as clear as what you see on the microscope. The images taken at 40X will seem to have less detail than the corresponding tissues seen under a microscope. The images taken at 400X often seem more clear than they do on the microscope, but the graininess of the image is worse at this magnification. Sometimes you will see what look like colored dots in the images. These are a result of the process used to digitize the images.
shape and size - The field of view on a microscope is circular. The image captured by our video camera is rectangular and smaller than the microscope's field of view. A structure that looks small on the microscope's field of view will look larger and take up more of the area in our images. This would cause our images to appear as if they were made at higher magnification if they were compared directly to what you see on a microscope.
color - We tried to match the color of the image as closely as possible to the color of the slide as seen through the microscope. Sometimes color was sacrificed to increase contrast, but they are very close. In any case, color should never be the primary cue for identifying histological structures.
artifacts - Artifacts such as bubbles, breaks in tissue sections, folds in the tissue (looks like a darker line across the slide), and uneven stain (looks like blotches of darker color) can be found on many prepared slides. If artifacts appear in our images, we will point them out so no one confuses them with histological structures.
depth of field - When you use a microscope, you can focus "up and down" on different levels within the tissue preparation. Most of the slides you use in lab are made from slices of tissue that are between 8 and 10 micrometers thick. On high power (400X), the microscope can only focus on part of the specimen. This requires the microscope user to focus at several levels to see all of the detail. We were not able to translate that experience to this web site.
loading time - We tried to keep the loading time as brief as possible, and it should not take more than few seconds for each page to load.
printing the images - We designed the pages at this site to make viewing on the web as easy as possible. We did not make any effort to make the images fit on standard printer paper. That's because the best way to use these images is on-line. If you try to print the images, you will find out that most sets require 2 pages, not one. If you do print any of the pages, be aware that either images or text might be cut off at the bottom of a page.
labels in images - Most labels are abbreviated from the name of the structure that is being described in the text, such as nuc for nucleus or sse for simple squamous epithelium. We used arrows and other symbols (like the asterisk, *) to point out structures that could not be adequately described in the text. Bars are used in many images to indicate the width of a tissue layer or a structure. All labels are referenced in the accompanying text.
1) Your text book and lab book contain excellent photomicrographs of most of the tissues and organs at this site. In many cases the images in the textbook are clearer. Each time you look at an image on this site, compare it to the corresponding images in your books. It seems strange, but the more different images you see of a tissue or organ, the easier it is to recognize it under the microscope. By doing this you end up using the most important structural features of the tissue or organ to identify it instead of getting stuck on one color or shape.
2) For each image you study, look for the unique characteristics that make that tissue or organ different from all of the other ones. It's the same process you use to identify your family or your car. It won't come automatically to you because you are looking at something you have never seen before, but you will pick it up quickly if you try.
3) You may find that you keep confusing two tissues because they look identical to you. In order for the process described in step 2. above to work, you have to compare the two images side by side to pick out the differences. Try tiling two images so that you can look back and forth between them easily. If you don't know how to tile windows on your monitor, look under WINDOW in the menu across the top of your screen.
Histology Slide Index
Tissue Slide Index - slides of epithelial, connective, muscle and nervous tissue
Organ Slide Index - slides of organs in the body systems covered in Human Anatomy
links to other explanatory pages on this site
process used to capture images
hints on how to use your microscope more effectively in lab
links to related sites:
Microbugz (ACC's microbiology help site)
ACC Biology Department Web Site (course descriptions, faculty contact information)
ACC LRS (library)